This perk greatly extends the player's detection radius, the equivalent of having a full 10 in Perception (in essence, ED-E's detection is substituted for your own). It also allows you to target cloaked enemies in V.A.T.S. mode. When paired with the Spotter perk given by Craig Boone, the player can effectively snipe targets from much greater distances.

This perk's effectiveness is limited indoors, since walls and different floors will prevent you from accurately assessing the location of any hostile targets. It will, however, give you a general idea of the numbers you'll be facing. Outdoors, on the other hand, it can allow you to perceive and bypass particularly dangerous foes without drawing their attention. It is possible to learn to identify some particularly dangerous enemies by their movement patterns. In particular, a closely packed group of 4-6 fast-moving enemies is almost certainly a nest of dangerous cazadores.

This perk will give you a bonus of 20-25% to hit against cloaked targets while using V.A.T.S.; however, the bonus is lost when an enemy uncloaks.

The added detection radius can make identifying immediate threats more difficult, since the compass does not give any information on the distance or height of enemies it picks up. In order to get an idea of the relative distance of different targets, move side to side a little while pointed at the targets. The less a target marker moves on the compass when you move side to side, the farther away the target is.